[small-prompt] add cpp attempt

Author: Microeinstein

unix/small-prompt/prompt.cpp

@@ -0,0 +1,363 @@
+#!/usr/bin/env -S bash -c "set -x; tail -n+2 \$0 | clang++ -x c++ -std=c++20 -march=native -Ofast -flto -Wfatal-errors -Wall -Wextra -pedantic - && ./a.out"
+// -Ofast -flto   -Og
+// C++
+#include <iostream>
+#include <iomanip>
+#include <format>
+
+#include <vector>
+#include <iterator>
+
+// C
+#include <cstdlib>
+
+// linux
+#include <sys/ioctl.h>
+#include <unistd.h>
+
+
+using
+    std::string, std::vector, std::format,
+    std::cout, std::cerr, std::endl;
+
+
+inline void concat(string& dest, const vector<string>& v) {
+    for (auto e : v) dest += e;
+}
+inline void concat(string& dest, const vector<char>& v) {
+    for (auto e : v) dest += e;
+}
+
+inline string concat(const vector<string>& v) {
+    string ret;
+    concat(ret, v);
+    return ret;
+}
+inline string concat(const vector<char>& v) {
+    string ret;
+    concat(ret, v);
+    return ret;
+}
+
+inline string join(string delim, const vector<string>& v) {
+    string ret;
+    if (v.size() == 0) return ret;
+    auto iter = v.begin();
+    ret += *iter;
+    for (advance(iter, 1); iter != v.end(); ++iter) {
+        ret += delim;
+        ret += *iter;
+    }
+    return ret;
+}
+
+inline void writelines(std::ostream& out, const vector<string>& v) {
+    for (auto s : v) out << s << endl;
+}
+
+
+inline auto get_term_cols() {
+    struct winsize w;
+    ioctl(0, TIOCGWINSZ, &w);
+    return w.ws_col;
+}
+
+inline string get_username() {
+    return string(cuserid(nullptr));
+}
+
+inline string get_workdir() {
+    char *raw = get_current_dir_name();
+    string ret{raw};
+    free(raw);
+    return ret;
+}
+
+inline bool check_env_def(const char* k) {
+    return !!std::getenv(k);
+}
+
+inline bool check_env_is(const char* k, const char* v) {
+    char *ptr = std::getenv(k);
+    if (!ptr) return false;
+    return string(ptr) == v;
+}
+
+
+/*
+ * https://wiki.archlinux.org/title/Bash/Prompt_customization
+ * https://man.archlinux.org/man/bash.1#PROMPTING
+ * https://invisible-island.net/xterm/ctlseqs/ctlseqs.html
+ * https://superuser.com/a/301355
+ *
+ *     <PS1>[PS2]<Enter><PS0>[PS3][PS4]
+ *     PROMPT_COMMAND can be used, but not for printing;
+ *         must use it to save status.
+ */
+
+namespace ansi {
+    string
+        esc   = "\033",
+        reset = "0",
+        bold  = "1",
+        reset_all = esc + "(B" + esc + "[m";
+
+    struct {
+        string cust256 = "38;5";
+        struct { string
+            black  = "30", red   = "31", green   = "32",
+            yellow = "33", blue  = "34", magenta = "35",
+            cyan   = "36", white = "37";
+        } dark;
+        struct { string
+            black  = "90", red   = "91", green   = "92",
+            yellow = "93", blue  = "94", magenta = "95",
+            cyan   = "96", white = "97";
+        } light;
+    } fg;
+    
+    vector rainbow_dark {
+        "196",  "202",  "208",  "214",  "220",  "226",  "190",  "154",  "118",  "82",
+        "46",   "47",   "48",   "49",   "50",   "51",   "45",   "39",   "33",   "27",
+        "21",   "57",   "93",   "129",  "165",  "201",  "200",  "199",  "198",  "197",
+    };
+    
+    vector rainbow_light {
+        "160",  "166",  "172",  "178",  "142",  "106",  "70",   "71",   "72",   "73",
+        "74",   "68",   "62",   "56",   "92",   "128",  "164",  "163",  "162",  "161",
+    };
+
+    
+    inline string fmt(vector<string> list) {
+        return concat({esc, "[", join(";", list), "m"});
+    }
+}
+
+namespace bash {
+    constexpr char Q1 = '\'',  Q2 = '"',  ESC = '\\';
+    
+    namespace ps { string
+        a     = "\x01",
+        b     = "\x02",
+        user  = "\\u",
+        cpath = "\\w",
+        cdir  = "\\W",
+        euid  = "\\$";
+    }
+
+    constexpr auto PROMPT_CMD = "PROMPT_COMMAND";
+
+    inline string quote1(string arg) {
+        string ret;
+        ret += Q1;
+        for (char& c : arg) {
+            if (c == Q1) concat(ret, {c, ESC, c});
+            ret += c;
+        }
+        ret += Q1;
+        return ret;
+    }
+    inline string quote2(string arg) {
+        string ret;
+        ret += Q2;
+        for (char& c : arg) {
+            if (c == Q2) ret += ESC;
+            ret += c;
+        }
+        ret += Q2;
+        return ret;
+    }
+    inline string noprint(string arg) {
+        return concat({ps::a, arg, ps::b});
+    }
+    inline string set(string k, string v) {
+        return concat({k, "=", v});
+    }
+    inline string var_(string v) {
+        return "$" + v;
+    }
+    inline string var(string v) {
+        return concat({"\"$", v, "\""});
+    }
+    inline string subsh(string arg) {
+        return concat({"\"$(",  arg,  ")\""});
+    }
+    inline string cmd(const vector<string>& v) {
+        return join(" ", v);
+    }
+    inline string cmds(const vector<string>& v) {
+        return join("; ", v);
+    }
+    inline string procsub(const vector<string>& v) {
+        return concat({"<(",  cmd(v),  ")"});
+    }
+    inline string func(string name, const vector<string>& v) {
+        return concat({name, "() { ", cmds(v), "; }"});
+    }
+}
+
+
+constexpr const char* PROMPT_MY = "_prompt_my";
+string PROG;
+
+
+namespace V {
+    string user  = get_username();
+    string dir   = get_workdir();
+    ushort tcols = get_term_cols();
+    bool is_root = geteuid() == 0;
+    bool is_long = user.length() + dir.length() + 4 > tcols / 2;
+    
+    bool is_vscode = check_env_is("TERM_PROGRAM", "vscode");
+    bool is_jetbr  = check_env_is("TERMINAL_EMULATOR", "JetBrains-JediTerm");
+    bool is_kate   = check_env_def("KATE_PID");
+    bool is_xterm  = check_env_def("XTERM_VERSION");
+    
+    bool as_light = is_vscode || is_jetbr;
+    bool as_simpl = is_long || is_kate || is_vscode || is_jetbr;
+    bool as_rever = is_xterm;
+    
+    vector<const char*>& rainbow = as_light ? ansi::rainbow_light : ansi::rainbow_dark;
+}
+
+
+namespace E { const char
+    *pr = "prompt",
+    *re = "resize";
+}
+
+
+using argnames = struct {  // type is pointer to unnamed struct
+    char *event;
+    char *print_i;
+}*;
+
+
+struct state {
+    string event = E::pr;
+    int rbow_i = V::is_root ? -1 : (V::as_light ? 6 : 8);
+    
+    static state read(char *args[]) {
+        state r;
+        auto a = reinterpret_cast<argnames>(args);
+        r.event = string(a->event);
+        r.rbow_i = std::stoi(a->print_i);
+        return r;
+    }
+    string write() {
+        using namespace bash;
+        return func(PROMPT_MY, { cmd({ "source", procsub({
+            PROG, "gen",  concat({"\"${1:-", E::pr, "}\""}),  std::to_string(rbow_i)
+        }) }) });
+    }
+};
+
+
+void shell_gen(char *args[]) {
+    using namespace ansi;
+    using namespace bash;
+    
+    auto s = state::read(args);
+    if (s.event == E::pr)
+        s.rbow_i = (s.rbow_i + 1) % V::rainbow.size();
+    
+    // cerr << TCOLS << "  " << USER << "  " << DIR << endl;
+    
+    /* DRAFTS
+     *   Resizing
+     *     { sleep 2; tput sc; tput khome; tput hpa 0; tput dch1; tput rc; } &
+     *   
+     *   Get background color
+     *     \e]11;?\a  ->  11;rgb:2323/2626/2727  ->  (OR)>7f
+     * 
+     *   Detect cursor not at column 1
+     *   Get last command return code
+     *   Print only last 2 parts of current dir
+     */
+    
+    string
+        rain  = V::rainbow[s.rbow_i],
+        lrain = noprint(fmt({reset, bold, fg.cust256, rain})),
+        drain = noprint(fmt({reset, fg.cust256, rain})),
+        luser = noprint(fmt({reset, V::is_root ? fg.light.red : fg.light.green})),
+        duser = noprint(fmt({reset, V::is_root ? fg.dark.red : fg.dark.green})),
+        white = noprint(fmt({reset,
+            V::as_light ? ""
+                : V::as_rever
+                    ? fg.light.black
+                    : fg.light.white })),
+        gray  = noprint(fmt({reset,
+            V::as_light ? ""
+                : V::as_rever
+                    ? fg.dark.black
+                    : fg.dark.white }));
+    
+    string PS1;
+    
+    if (V::as_simpl)
+        PS1 = concat({gray, ps::cdir, " ",   lrain, ps::euid,   drain, "> ",  white});
+    else
+        PS1 = concat({
+            lrain, ps::user,   white, ") ",   gray, ps::cpath, " ",
+            luser, ps::euid,   duser, "> ",   white
+        });
+
+    writelines(cout, {
+        set("PS1", quote1(PS1)),
+        s.write(),
+    });
+}
+
+
+void shell_init() {
+    using namespace bash;
+    state defaults;
+    
+    writelines(cout, {
+        defaults.write(),
+        // "trap - SIGWINCH",
+        // format("trap '{} resize' SIGWINCH", PROMPT_MY),
+        set("PS0", subsh("tput sgr0")),
+        V::as_rever ? "printf '\\e[?5h\\e[?30h'" : "",
+        format(
+            //R"([[ "${{{0}[*]}}" =~ .*\ ?{1}[\ \;].* ]] || {0}+=('{1}'))",
+            R"([[ "${{{0}[*]}}" == *{1}* ]] || {0}+=('{1}'))",
+            PROMPT_CMD, PROMPT_MY
+        ),
+    });
+}
+
+
+void print_help() {
+    using namespace ansi;
+    cerr << format(1 + R"h(
+Usage: {0} <args..>
+
+Arguments:
+    help, --help, -h    Show this message.
+    init                Print shell script to be evaluated.
+    gen <state..>       Run at {1}.
+
+Load with {3}source <({0} init){2} in your {3}~/.bashrc{2}.
+)h", PROG, bash::PROMPT_CMD, reset_all, fmt({fg.light.magenta}));
+}
+
+
+int main(int argc, char *argv[]) {  // $0 <cmd>
+    PROG = argv[0];
+    if (argc <= 1)
+        return print_help(), 1;
+
+    string arg = argv[1];
+    
+    if (arg == "help" || arg == "--help" || arg == "-h")
+        return print_help(), 0;
+    if (arg == "init")
+        return shell_init(), 0;
+    if (arg == "gen")
+        return shell_gen(&argv[2]), 0;
+
+    cerr << "Unknown argument: " << arg << endl;
+    return print_help(), 1;
+}
+